How Much Do Positive or Negative Expectations Affect Performance?

Even from a very early age, I remember being told to imagine things going well. The idea, was that if I could imagine a positive outcome, I'd be more likely to expect good things, which would help me perform better. Is this just something that people say? Or do our expectations really have a meaningful effect on how we perform? A classic 1972 study illustrates the effect that positive or negative expectations can have on performance. Get all the nerdy details here: How Much Do Positive or...